A Single-Stage Pulse Tube Cryocooler for Horizontally Cooling HTS MRI Probe

A single‐stage GM type pulse tube cryocooler, model HPT10, has been developed to operate horizontally to meet certain cooling requirements (including applications such as high temperature superconducting (HTS) MRI probe coils, detectors, etc). A rotary valve (with motor) is physically separated from a pulse tube expander through a 2.1 meter stainless steel flexible line. The HPT10 provides 16.0 W at 77 K when operating in a horizontal position and 17.6 W at 77 K when operating in a vertical position, thus demonstrating only small performance degradation when operating horizontally. The HTS probe coil cooled by this type pulse tube cryocooler will significantly improve the image quality of MRI systems.